Onchidella J.E. Gray, 1850

Dayrat, Benoît, Zimmermann, Sara & Raposa, Melissa, 2011, Taxonomic revision of the Onchidiidae (Mollusca: Gastropoda: Pulmonata) from the Tropical Eastern Pacific, Journal of Natural History 45 (15 - 16), pp. 939-1003 : 942-943

Onchidella J.E. Gray

Onchidella J.E. Gray in M.E. Gray, 1850.

Arctonchis Dall, 1910 (a section name).

Occidentella Hoffmann, 1929 .

Peroniella Starobogatov, 1976 .

For more information, see Dayrat 2009.

Type species

Onchidella nigricans (Quoy and Gaimard, 1832) , by subsequent designation ( Fischer and Crosse 1878). Dall (1910) thought that Hermannsen (1852) had subsequently designated the type species. However, Hermannsen only listed O. nigricans as one of the species belonging to the genus, whereas Fischer and Crosse unambiguously cited O. nigricans as the type species.

Remarks

The generic name Oncidiella Fischer and Crosse, 1878 is an unjustified emendation of Onchidella .

Diagnosis

Dorsal notum without branchial gills. Dorsal papillae with no dorsal eyes. Two oral lobes not fused medially. Hyponotal line present. Male genital opening on right lateral side of right oral lobe. Intestine usually of type IV. Reno-pulmonary complex bilaterally symmetrical. Marginal glands in body wall. Visceral cavity not divided longitudinally by a septum. Accessory gland in the penial complex absent. Rectal gland absent.

Remarks

Given that the onchidiid supra-specific phylogenetic relationships are still unknown ( Dayrat 2009; see Discussion), it is difficult to delineate and define Onchidella so that it could correspond to a clade (although the identification of Onchidella has remained much less problematic than for other onchidiid taxa, especially Onchidium ). In particular, it is difficult to evaluate whether Hoffmannola is clustered within Onchidella , or if both taxa are separate. At this stage, it also is unclear whether the characters that have been traditionally accepted for Onchidella (e.g. Labbé 1934; Britton 1984) and are provided in the above diagnosis are synapomorphies, autapomorphies, or symplesiomorphies. However, the characters provided in the diagnosis above are shared by Onchidella nigricans (Quoy and Gaimard, 1832) , the type species of the genus, as well as all valid species described below, which one can thus reasonably continue to classify in Onchidella , at least for the time being.